Radio signaling system



Julie 8 ,1926. 1,587,657

F. A; KOLSTEP RADIO SIGNALING SYSTEM Filed Dec. 5, 1921 2 Sheets-Sheet 1 F161,. F1 2 V 23 I 25 a 29 't fiz WITNESS INVENTOR fiaioamcK A. Kola-r52.

ATTORNEYS 1 June 8, 1926. V 1,587,657

- F.VA. KOLSTER RADIO 5 IGNALI NG SYSTEM il' dpes. 5, 1921 2 Sheet s-Sheei: 2 w I- 77 FIG. 6.

WITNESS 21 ATTORNEYS Patented June 8, 1926.

FREDERICK A. KOLS'IER, 0F BURLINGAME, CALIFORNIA, ASSIGNOR TO FEDERAII TELEGRAPH COMPANY, OF SAN FRANCISCO, CALIFORNIA, A. CORPORATION OF CALIFORNIA.

RADIO SIGNALING SYSTEM.

Alpplication filed December 5, 1921. Serial mi. 519,954..

My invention relates to a radio signaling system and more particularly to a system for receiving signals from or sending signals to a selected point; in other words, a sys- 'tem having unidirectional properties. Such a system broadly has been described in several prior applications filed in my name, antitled Radio method and apparatus, Serial No. 27 4,054, filed January 30, 1919, which was patented Feb. 27, 1923, and bears Patent Number 1,447,165, and another entitled the same, but having Serial No. 426,503, filed November 26, 1920. The present appllcation deals with modifications which are better adapted under certain conditions to send and to receive unidirectional signals.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at len h in the following description, where I s all outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming art of the present specification. In the drawings, I have shown several embodiments of my invention but it is to be understood that I do not limit myself to these forms, since the invention as expressed in the claims may be embodied 1n other forms as well.

Referring to the drawings:

Figure 1 represents schematically a receiving system embodying one form of my inventlon;

Fig. 2 represents a modification of Fig. 1 in, which inductors replace some of the capacitances;

Fig. 3 shows another modification of Fig. 1;

Fig. 4 shows a scheme somewhat similar to Fig. 3, except that certain condensers are eliminated, and inductances are added;

Fi 5 shows a further modification with a di erenttype of aerial and tuning circuits, but having characteristics similar to those of the modification shown in Fig. 2:

Fig. 6 shows a form employing a scheme for transmitting signals in connection with a slightly modified form of apparatus;

Fig. 7 shows a receiving system employing a modified form of coil in place of the rotatable one shown in the other figures; and

Fi s. 8, 9 and 10 are diagrams for explaining t e unilateral characteristics of circuits of the type shown.

As explained in the applications heretofore identified the circuits I employ for n11- ilateral reception or transmission include a coil having a considerable inductance and the direction of the axis of which may be variable, as by bodily rotation, and a condenser associated with the coil in such a way that a resonant circuit is obtained as regards the oscillations to be received or transmitted. With no other elements at all, it is found that maximum signaling effects are produced in the direction of the plane of the coil; that is, perpendicular to its axis. If now an antenna circuit or other oscillation circuit of the ordinary sort be set up, incorporating this coil circuit in such a way that the antenna current has two paths through the coil, its directional effect may be emphasized by dividing the current unevenly between the two parallel aths. The result is a transfer of energy etween the coil circuit and the antenna circuit. By careful adjustment of the degree and direction of this transfer by unbalancing, it is possible to obtain a very pronounced effect; thus the coil circuit may be made so sensitive that its signaling effect is a maximum in one direction, which gradually decreases to zero in a direction 180 dis laced, and then gradually increases again or direction between 180 and the complete circle. The directional effect may be represented by a cardioid, with the origin at the cusp.

When the system is used for receiving or detecting, it is found that by unbalancing the parallel paths through the flat coil to the proper extent, a maximum response is obtained in the coil circuit when the lane of the coil is pointing toward the station, and a minimum response when the coil occupies a position 180 dis laced from the former one. Due to this 0 aracteristic, the system may be used as a direction finder or an interference preventer.

The foregoing outline of the operation of the system is disclosed in the prior applications heretofore identified, and it has been repeated here in an abbreviated form for the sake of coherence. The present invention deals with a multiplicity of alternative forms in which the receiving or transmitting circuits may be embodied.

Thus, Fig. 1 represents a receiving circuit. The antenna or oscillation circuit includes the earth connection 11, the inductance coil 12 with a shunted, adjustable capacity 13,

cuit includes a coil 15, wound as described -in the prior applications, the adjustable capacity 16, and the inductance 17 The aerial '14 connects at 18 to a central turn of-coil 15.

directional e The coil 12 connects at 19'between two adjustable condensers 20 and 21 which are joined in series across the coil 15. These two condensers are simultaneously adjust-. able in opposite directions; that is, as the value of 2l'is increased, that of '20 is de-- creased, and vice versa. If the capacities 20 and 21 have e ual values, then there is least fi ect. -By adjusting the condensers 20 and 21 carefully, the best directional effect may be obtained. The adjustment of these condensers does not destroy the tuning of the antenna circuit, since the has an inductance of a relatively small value.

as compared with that of coil 15. The

amount of current-circulating in the closedv coil. path depends not only upon the directionof the plane of the coil but also upon the amount of energy transferred between the antenna circuit and the closed coil circuit. Thisamount is determined by the de gree of unbalancing of the condensers 20 and'21. It is evident also that the detector circuit, or a transmitter circuit, may be coupledat any portion of the system which is sensitive to an exchange of ener between the antenna or oscillation. circuit and the closed coil circuit. Thus, the coupling of coil 24 may be effected to coil 12 as 'well as to coil 17 Other forms of reactances may be sub-.

stituted for the condensers 20 and 21. Thus, in Flg. 2, the inductors 25 and 26 are usedv to replace these condensers. The connections to the lnductors are made varlable; 27 and 28 being so arranged as to move in unison for tuning the antenna circuit. The connections 29 and 30 however are arranged to move in opposite directions simultaneously; that is, while connection 29 moves up, connection 30 moves down, and vice versa. In this way, the proper degree of unbalance is produced between the closed coil circuit and the antenna circuit. The detector circuit as before includes coil 24, condenser 23, and

the raised aerial 14. This aerial 14 may be entirely omitted if the capac1ty'between the earth and the other portlons of the circuit is sufliciently great. A closed cmtating the transfer of ener the detector; 22. Bywell knownv changes, this circuit maybe made a transmitting circuit. '3

Other means may be provided for facilibetween the closed coil circuit and the o'scillationcircuit. For-example, in Fig. 3 is illustrated an inductive coupling 31 between the two circults. For convenience the coil 32 which corresponds to coil 12 of Fig. 1 is utilized for one of the elements in theinductive. cou ling.

.With this scheme of connections, it is not essential to have adjustable condensers or' other forms of reactance Thus in this figure the condensers 33 and 34 are shown as non-adjustable.

' The detector circuit ineluding detector 22 is arranged as before.

The degree anddirection of energy transfer between the closed coil circuit and the antenna circuit is effected by properly setting the adjustment of the coupling 31.

Fig. 4 is similar to Fig. 3 in that the.

transfer of energy between the two circuits is eiiected by a variable. inductive coupling 35. between the two circuits; the tuning of the antenna circuit in this instance is eliected by the variable inductors 36 and'37, in the manner described in connection with Fig.2. It is not necessary, however, to unbalance the coils 36 and 37 as in Fig. 2. A detector or receiver circuit may be conveniently arranged in eitherthe coil circuit or in the antenna circuit; in the present instance, a

= detector 22 is shown coupled -'to the closed coil circuit. 4

Another embodiment of the invention is shown in Fig. 5. aerial shown in the other figures need not be adhered to and there may be substituted therefor a single horizontal wire 38. In this case the lumped inductance of the oscillation circuit.comprises the two adjustable inductors 39 and 40. The taps 41 and 42 are simultaneously movable but in the same direction, and are used for tuning the antenna or oscillation circuit. Adjustable condensers 43 and 44 in each. branch circuit may also be providedfor tuning. Taps 45 and 46 are arranged on coils 39 and 40 so that as one" moves up the other moves down, whereby any degree of unbalance may be obtained in the two parallel paths between points 47 and 48 of the antenna circuit. A detector or transmitter may be connected in a manner similar to that described hereinbefore.

In Fig. 6, another embodiment is shown, in which the aerial 49 may be rendered active or inactive by means of a switch 50. A source of high frequency oscillations 51.is h re shown for transmitting signals, in, series with the adjustable condenser '52 and a coil 53 which is in inductive relation to the coil 54 in the closed coil circuit. A coil 55 is arranged symmetrically to coil 54 so as to obtain a balance so far as inductance is con- The particular form of cerned. These coils ma preferably be made adjustable as shown. ondensers 56 and 57 serve as described he'reinbefore in connection ture, and is completely closed. A pair of variable taps 59, are so arranged that they may be made to include any angle between them on the coil 58. This adjustability is made use of for tuning a closed coil circuit including the coil 58, taps 59, 60, adjustable inductors 61 and 62, and the adjustable condenser 63. It is seen from the connections that the current in this closed circuit has two paths through coil 58 from tap 59 to tap 60,

.one through the left hand portion of the coil, and the other through the right hand portion. This closed circuit may be tuned either by adjusting the condenser 68 or by varying the angle between the two taps 59, 60. The oscillation circuit, which includes the inductor 64 coupled to the coil 61, and the adjustable condenser 65 in parallel thereto, may be tuned by adjusting this condenser. Use is also made of the adjustable condensers 56 and 57, which operate as in Fig. 6 to cause the desiredunbalance. Either a detector circuit or a transmitter circuit may be used with this'arrangement; in the present instance, an 'audion detector circuit is shown, coupled to the coil 62 of the closed coil circuit. This circuit comprises the usual coupling coil 66, condenser 67 in parallel therewith, anaud'ion 68 having a heated filament 69, grid 70, and plate 71. The grid circuit is in parallel with the condenser 67, and the plate circuit includes a translator 72 which may be used directly or for further amplification.

The directional efi'ects of the system just described are such that when the line 73 is drawn bisectingthe angle between the taps 59, 60, then the direction of maximum respouse or radiation is along line 74 at right angles to the line 73. If the taps 59 and 60 be permanently arranged to be diametrically opposite each other then line 7 4 will coincide with the line passing through the two taps.

The various unidirectional eflects are illustrated in Figs. 8, 9 and 10. If there is no substantial interchange of energy between the antenna or oscillation circuit and the closed coil circuit, the characteristics are illustrated in Fig. 8. Radiation at a definite wave lengthAzo 01' from the direction of station 77 1s a maximum, wh1le 1t IS a minimum or zero to or from the directions of stations 76 an 78. The unidirectional effect may identified. For intermediate points,

aptly becompared to a figure 8, at the center of which the closed coil-15 is placed with its plane in the lon itudinal axis of the 8. To. obtain the con ition of no interchange of energy between the two paths,the antenna or oscillation circuit may be entirely open or else detuned with respect" to the wave length of the radiations. Another way is to make the path of the antenna current symmetrical with respect to the closed coil path. This may be readily accomplished by making capacities 20 and 21 equal in the modification shown in Fig. 1 or by making the inductances 25 and 26 equal in Fig. 2. In the other figures, analogous methods for accomplishing the same result are self-evident. The closed coil path should preferably be tuned to the radiations it is desired to send or receive.

If, however, the antenna circuit be also tuned to the radiations, varying eliects can nevertheless be obtained by determining the amount of energy interchange between the two paths. chosen, the figure 8 becomes a car ioid, as explained in the applications hereinbefpre asor example when the energy supplied from the antenna or oscillation path to the closed coil circuit is less than that directly received by this circuit, an eliect something like that illustrated in Fig. 9 is obtained. Here one of the loops is much larger than the other.

This characteristic of course is for a definite wave length, and at this wave length, substantially no energy can be supplied to or' If this amount be pro erly received from the stations 79 and 80, but a maximum amount can be supplied to or received from station 81. The angular relation of the directions in which a maximum effect and a minimum effect can be obtained is controllable to a certain extent by controlling the amount of energy interchanged between the cl-osed coil circuit and the antenna circuit. Thus, interference may be pre vented between stations having varying rel ative angular positions with respect to the coil 15. The mode of operation to secure this result, involves bringing the plane of coil 15 into line with the station 81, then regulating the energy interchange between the dirrectional and non-directional systems until a line drawn from the interteringstation falls outside of either loop.

With the systems described, it is also quite feasible to signal either of two stations which are directly in line as regards the operating coil. Such a condition is illustrated in Fig. 10, where stations 84 and 85 are substantially in a straight line upon which is also located the center of the coil 15. These stations have of course different wave lengths. The method of excluding only one of the stations while obtaining a maximum effect with respect to the other station will be described for receiving, but it is to be forsending to either of the two stations, with appropriate changes. 'Let us assume that station isthe selected station from which --the radiations are to be received. The closed coilcircuit is tuned to receive the radiations from this source, while the antenna or oscillation circuit is tuned to the radiations from the interfering station 84. Since under such conditions there can be substantially no in terchange of energy ofthewvave length of station 85 between the closed coilcircuit and the oscillation circuit, the directional char' acteristics as regards. tlus station maybe represented by the figure 8 which is marked with the reference numeral 83. However, by properly manipulating the unbalancing means in the circuits, it is ossible to transfer energy of the wave lengt of interfering station 84 to the coil circuit. This unbalancing may in fact go so far'that the unidirectional characteristics with respect to this station will take the form of'the cardioid 82. This effect is best when the wave lengths of the two stations 84 and 85 differ but slightly, for then the closed coil circuit can receive an appreciable amount of energy from station 84: even if it is sharply tuned to the wave length of station 85. If the characteristics such as 82 and 83 are obtained for the energy received from stations 85 and 84 respectively, the coil circuit responds to a maximum extent to the radiations from station 85, but no substantial response is obtained from the station 84. Thus, interference from this station-isprevented.

Efiects similar to that just discussed may be obtained by superposing the unidirec-,

tional characteristic even when the stations are not exactly in the same direction.

The term antenna circuit as used in the description and in the claims is used interchangeably with the term oscillation. circuit; 'both terms are meant to apply to an ordinary circuit for radiating or receiving energy in the form of electromagnetic waves.

; Similarly, the term signaling circuit is meant to apply either to a transmitting device or to a receiver circuit.

I claim:

1. In apparatus of the character described, a non-uniform circuit including a rotatable coil, and providing direct energy interchange with a. natural medium, cle ments which together with this coil form a uniform oscillation circuit, means providing foran interchangeof energy between the non-uniform and the uniformv circuit, a signaling circuit, and an inductive coupling between the signaling circuit and the nonuniform circuit, this being the only coupling between the signaling circuit and the remainder of the apparatus.-

2. In apparatus of the character described,

interchange with La natural medium, said circuit including a coil-and an vadjustable condenser, a pair of oppositely variable condensers n parallel with the (3011,,IHB3I1S for completing another oscillation Iclr'cuit' through, the coil, in which thereiare two paths in'pa'rallel, each path including'one of the last named condensers and a portion of the coil, a signaling circuit, and an inductive couplin between this circuit and that portion of t e closed coil circuit which is Y included only in this coil circuit, this being the only inductive coupling between the signaling circuit and. the remainder of the 'apparatus. I

. 3.'In apparatus of the character described, a closed circuit for providing direct energy interchange with a natural medium, said circuit including acoil and an adjustable condenser, a pair of oppositely variable reactances in parallel with the coil, means for completing another oscillation circuit through the coil in which there-are two paths in parallel, each path including one of the reactances and a portion of the coil, a signaling circuit, and an inductive coupling between this circuit and that portion said elements including two oppositely vanable condensers, one in each of the parallel paths, whereby an adjustable amount of energy may be transferred between the two circuits, a signaling circuit and .an inductive coupling between thesignaling circuit and the coil circuit, this being the only cou-.

pling between the signaling circuit and the remainder of the apparatus.

5. In an apparatus of the class described, a closed circuit for providing direct energy interchange with a natural medium, sa1d circuit including a coil and a pair of adjustable inductors in series with the coil, elements which with the coil form another oscillation circuit so that this latter circuit has two paths in parallel through the coil, said elements including two oppositely vari able condensers, one in each of the "parallel paths, whereby an adjustable amount of energy maybe transferred between the ,two

a closed circuit forproviding directenergy I understood that the method may also be used circuits, and a signaling circuit inductively I coupled to one of the'adjustable inductors.

6. In an apparatus of the class described, a closed circuit for providing direct energy interchange with a natural medium, said circuit including a coil and a pair of adjustable inductors in series with the coil, elements which with the coil form another oscillation circuit so that this latter circuit has two paths in parallel through the coil, said elements including means for causing an interchange of energy between the two circuits, and a signaling circuit inductively coupled to one of the adjustable inductors".

7. The method of signaling by radio between one station and either of two others both of which are substantially in the same line and inthe same direction as regards the other station, and which utilize difi'ering frequencies, the other station having a uniform oscillation circuit and a closed coil circuit, which consists in tuning the oscillation circuit to one of the stations and, the coil circuit to the other, whereby when the plane of the coil is substantially in line with the stations, signaling may be produced between one of the two stations in line to the substantial exclusion of the other.

8. In a system of signaling between one station and either of two others which are substantially 'in the same line and in the same direction as regards the first station, the wave lengths associated with the other two being slightly different, the method of signaling between the first station and either [of the other two to the substantial exclusion of the third, which consists in superposing at the first mentioned station the directional characteristics of a simple closed radio circuit including a coil for one of the two wave lengths, and the directional characteristic of a combination of such a closed circuit with a uniform oscillation circuit for the other wave length.

9. In a system of signaling between one station and either of two others, which are substantially in the same line and in the same direction as regards the first station,

the wave lengths associated with these two,

being slightly different, the method of signaling between the first station and either of the other two to the substantial exclusion of the third, which consists in tuning a closed circuit including a coil to one of the two wave lengths, turning the plane of the coil in the direction of signaling, tuning to the other wa'ye length a uniform oscillation circuit between which and the coil circuit an energy transfer is possible, and adjusting the amount of energy transfer until sig naling with energy of the wave length to which the oscillation circuit is tuned, is prevented between the stations.

In testimony whereof, I have hereunto set m hand. y FREDERICK A. KOLSTER. 

